So I'm not sure if your question is "why are there extra entries" or "why isn't the high Sierra drive showing up as an option", or something else. The former is probably something to do with how clover builds and stores entries on the boot screen in combination with your motherboard's bios, and my takeaway is that extra entries can build up in some circumstances. There are posts on cleaning up the clover boot selection screen. As to the second question, in order for clover to see a high Sierra drive that's been converted to apfs (if you did), you need to add apfs.efi to your CLOVER/EFI/drivers64UEFI (assuming UEFI boot vs. legacy).